diff --git a/runtime/include/http.h b/runtime/include/http.h
index df3b9f5..cab6f34 100644
--- a/runtime/include/http.h
+++ b/runtime/include/http.h
@@ -13,12 +13,17 @@
 #define HTTP_MAX_QUERY_PARAM_COUNT  16
 #define HTTP_MAX_QUERY_PARAM_LENGTH 32
 
-#define HTTP_RESPONSE_200_OK    \
-	"HTTP/1.1 200 OK\r\n"   \
-	"Server: SLEdge\r\n"    \
-	"Connection: close\r\n" \
+#define HTTP_RESPONSE_200_TEMPLATE \
+	"HTTP/1.1 200 OK\r\n"      \
+	"Server: SLEdge\r\n"       \
+	"Connection: close\r\n"    \
+	"Content-Type: %s\r\n"     \
+	"Content-Length: %lu\r\n"  \
 	"\r\n"
 
+/* The sum of format specifier characters in the template above */
+#define HTTP_RESPONSE_200_TEMPLATE_FORMAT_SPECIFIER_LENGTH 5
+
 #define HTTP_RESPONSE_400_BAD_REQUEST  \
 	"HTTP/1.1 400 Bad Request\r\n" \
 	"Server: SLEdge\r\n"           \
@@ -61,10 +66,6 @@ http_header_build(int status_code)
 	const char *response;
 	int         rc;
 	switch (status_code) {
-	case 200:
-		response = HTTP_RESPONSE_200_OK;
-		http_total_increment_2XX();
-		break;
 	case 400:
 		response = HTTP_RESPONSE_400_BAD_REQUEST;
 		http_total_increment_4XX();
@@ -100,8 +101,6 @@ static inline size_t
 http_header_len(int status_code)
 {
 	switch (status_code) {
-	case 200:
-		return strlen(HTTP_RESPONSE_200_OK);
 	case 400:
 		return strlen(HTTP_RESPONSE_400_BAD_REQUEST);
 	case 404:
diff --git a/runtime/include/http_session.h b/runtime/include/http_session.h
index ad2b6cf..5e3acf8 100644
--- a/runtime/include/http_session.h
+++ b/runtime/include/http_session.h
@@ -38,6 +38,8 @@ enum http_session_state
 	HTTP_SESSION_SENT_RESPONSE
 };
 
+#define HTTP_SESSION_RESPONSE_HEADER_CAPACITY 256
+
 struct http_session {
 	enum http_session_state state;
 	struct sockaddr         client_address; /* client requesting connection! */
@@ -45,7 +47,7 @@ struct http_session {
 	struct http_parser      http_parser;
 	struct http_request     http_request;
 	struct vec_u8           request_buffer;
-	const char             *response_header;
+	char                    response_header[HTTP_SESSION_RESPONSE_HEADER_CAPACITY];
 	size_t                  response_header_length;
 	size_t                  response_header_written;
 	struct vec_u8           response_buffer;
@@ -161,13 +163,25 @@ http_session_free(struct http_session *session)
  * @param status_code
  */
 static inline void
-http_session_set_response_header(struct http_session *session, int status_code)
+http_session_set_response_header(struct http_session *session, int status_code, const char *content_type,
+                                 size_t content_length)
 {
 	assert(session != NULL);
-	assert(status_code >= 100 && status_code <= 599);
-
-	session->response_header        = http_header_build(status_code);
-	session->response_header_length = http_header_len(status_code);
+	assert(status_code >= 200 && status_code <= 599);
+
+	if (status_code == 200) {
+		session->response_header_length = snprintf(session->response_header,
+		                                           HTTP_SESSION_RESPONSE_HEADER_CAPACITY,
+		                                           HTTP_RESPONSE_200_TEMPLATE, content_type, content_length);
+	} else {
+		size_t header_len = http_header_len(status_code);
+		size_t to_copy    = HTTP_SESSION_RESPONSE_HEADER_CAPACITY < header_len
+		                      ? HTTP_SESSION_RESPONSE_HEADER_CAPACITY
+		                      : header_len;
+
+		strncpy(session->response_header, http_header_build(status_code), to_copy - 1);
+		session->response_header_length = to_copy;
+	}
 }
 
 static inline void
@@ -215,7 +229,6 @@ static inline int
 http_session_send_response_body(struct http_session *session, void_star_cb on_eagain)
 {
 	assert(session != NULL);
-	assert(session->response_buffer.buffer != NULL);
 
 	while (session->response_buffer_written < session->response_buffer.length) {
 		ssize_t sent =
@@ -367,11 +380,14 @@ http_session_receive_request(struct http_session *session, void_star_cb on_eagai
 		                   (char *)&session->request_buffer.buffer[session->request_buffer.length],
 		                   session->request_buffer.capacity - session->request_buffer.length, on_eagain,
 		                   session);
-		if (bytes_received == -EAGAIN) goto err_eagain;
+		if (bytes_received == -3) goto err_eagain;
 		if (bytes_received == -1) goto err;
 		/* If we received an EOF before we were able to parse a complete HTTP message, request is malformed */
 		if (bytes_received == 0 && !session->http_request.message_end) goto err;
 
+		assert(bytes_received > 0);
+		assert(session->request_buffer.length < session->request_buffer.capacity);
+
 		session->request_buffer.length += bytes_received;
 
 		ssize_t bytes_parsed = http_session_parse(session, bytes_received);
diff --git a/runtime/include/sandbox_set_as_error.h b/runtime/include/sandbox_set_as_error.h
index 4b949d8..35b6be9 100644
--- a/runtime/include/sandbox_set_as_error.h
+++ b/runtime/include/sandbox_set_as_error.h
@@ -59,7 +59,7 @@ sandbox_set_as_error(struct sandbox *sandbox, sandbox_state_t last_state)
 	admissions_control_subtract(sandbox->admissions_estimate);
 
 	/* Return HTTP session to listener core to be written back to client */
-	http_session_set_response_header(sandbox->http, 500);
+	http_session_set_response_header(sandbox->http, 500, NULL, 0);
 	sandbox->http->state = HTTP_SESSION_EXECUTION_COMPLETE;
 	http_session_send_response(sandbox->http, (void_star_cb)listener_thread_register_http_session);
 	sandbox->http = NULL;
diff --git a/runtime/include/sandbox_set_as_returned.h b/runtime/include/sandbox_set_as_returned.h
index f54e49a..3a20fc9 100644
--- a/runtime/include/sandbox_set_as_returned.h
+++ b/runtime/include/sandbox_set_as_returned.h
@@ -51,7 +51,8 @@ sandbox_set_as_returned(struct sandbox *sandbox, sandbox_state_t last_state)
 	sandbox_state_totals_increment(SANDBOX_RETURNED);
 	sandbox_state_totals_decrement(last_state);
 
-	http_session_set_response_header(sandbox->http, 200);
+	http_session_set_response_header(sandbox->http, 200, sandbox->route->response_content_type,
+	                                 sandbox->http->response_buffer.length);
 	sandbox->http->state = HTTP_SESSION_EXECUTION_COMPLETE;
 	http_session_send_response(sandbox->http, (void_star_cb)listener_thread_register_http_session);
 	sandbox->http = NULL;
diff --git a/runtime/src/listener_thread.c b/runtime/src/listener_thread.c
index 14202cb..5ab1c65 100644
--- a/runtime/src/listener_thread.c
+++ b/runtime/src/listener_thread.c
@@ -164,7 +164,7 @@ on_client_request_arrival(int client_socket, const struct sockaddr *client_addre
 		/* Failed to allocate memory */
 		debuglog("Failed to allocate http session\n");
 		session->state = HTTP_SESSION_EXECUTION_COMPLETE;
-		http_session_set_response_header(session, 500);
+		http_session_set_response_header(session, 500, NULL, 0);
 		on_client_response_header_sending(session);
 		return;
 	}
@@ -185,13 +185,13 @@ on_client_request_receiving(struct http_session *session)
 		/* Failed to grow request buffer */
 		debuglog("Failed to grow http request buffer\n");
 		session->state = HTTP_SESSION_EXECUTION_COMPLETE;
-		http_session_set_response_header(session, 500);
+		http_session_set_response_header(session, 500, NULL, 0);
 		on_client_response_header_sending(session);
 		return;
 	} else if (rc == -1) {
 		debuglog("Failed to receive or parse request\n");
 		session->state = HTTP_SESSION_EXECUTION_COMPLETE;
-		http_session_set_response_header(session, 400);
+		http_session_set_response_header(session, 400, NULL, 0);
 		on_client_response_header_sending(session);
 		return;
 	}
@@ -208,7 +208,7 @@ on_client_request_received(struct http_session *session)
 	if (route == NULL) {
 		debuglog("Did not match any routes\n");
 		session->state = HTTP_SESSION_EXECUTION_COMPLETE;
-		http_session_set_response_header(session, 404);
+		http_session_set_response_header(session, 404, NULL, 0);
 		on_client_response_header_sending(session);
 		return;
 	}
@@ -221,7 +221,7 @@ on_client_request_received(struct http_session *session)
 	uint64_t work_admitted = admissions_control_decide(route->admissions_info.estimate);
 	if (work_admitted == 0) {
 		session->state = HTTP_SESSION_EXECUTION_COMPLETE;
-		http_session_set_response_header(session, 429);
+		http_session_set_response_header(session, 429, NULL, 0);
 		on_client_response_header_sending(session);
 		return;
 	}
@@ -232,7 +232,7 @@ on_client_request_received(struct http_session *session)
 	if (unlikely(sandbox == NULL)) {
 		debuglog("Failed to allocate sandbox\n");
 		session->state = HTTP_SESSION_EXECUTION_COMPLETE;
-		http_session_set_response_header(session, 500);
+		http_session_set_response_header(session, 500, NULL, 0);
 		on_client_response_header_sending(session);
 		return;
 	}
@@ -242,7 +242,7 @@ on_client_request_received(struct http_session *session)
 		debuglog("Failed to add sandbox to global queue\n");
 		sandbox_free(sandbox);
 		session->state = HTTP_SESSION_EXECUTION_COMPLETE;
-		http_session_set_response_header(session, 429);
+		http_session_set_response_header(session, 429, NULL, 0);
 		on_client_response_header_sending(session);
 	}
 }